Meet the Ar 231, which seemed like a good idea at the time. It was a tiny single seat folding floatplane intended to be carried on submarines. Subs are not noted for interior space so it was designed to fit into a tube 2m wide. Like this in fact.

Opened out it looked like this:

Advertisement

Its designers were not wedded to the idea of symmetry and so allowed themselves this odd looking wing which made folding easier.

In the event it turned out to be a flop.